This use case could be satisfied with the xpath scheme in XPointer, but I'm
not finding any processors that support it, or even any information about
that scheme.

The lack of such support led to the DocBook TC developing the DocBook
assembly system in the forthcoming DocBook 5.1. That system allows you to
rewrite a document as an assembly of modular references. An assembly is
then processed into a normal DocBook document for rendering. The assembly
specification supports this use case through the contentonly="1" attribute
on the module element.

I read through the new spec and it looks good. I have just a couple of
comments.

1. The first example in C.6 uses frigid="line=2,6". Unless you are
introducing a

refrigerator identification system, I think that should be fragid. 8^)

It also says "There are four of them", but I think lines="2,6" is
inclusive, so
that would be five lines, no? The output example seems to include the
fifth

blank line that puts </pre> on its own line.
2. In C.7, the example of attribute copying, I would like to see a second

example that replaces xml:id. I presume that works even when the xpointer
is

using the xml:id in the source file to fetch the content.

Regarding xml:id fixup, this feature only applies to the top-level
included
element. If there are duplicate xml:ids in its descendants, then further
fixup

will be required after inclusion, right?

3. This document does not address any improvements to xpointer. I still
use
xsltproc for its implementation of the xpointer() scheme of xpointer, but
that
scheme never became a standard. What is the status of using some kind of
xpath

syntax in xpointer?

Hi,

Having recently moved to docbook 5, I also deeply miss the xpointer()
scheme. The functionality that I sorely miss is the possibility to
reference a tag using its ID, and xinclude everything that's within the
referenced tag, except the tag itself:
<xi:include href="blah.xml" xmlns:xi="http://www.w3.org/2001/XInclude&quot;
xpointer="xpointer(//note[@id='mynote']/*)"/>

Supporting this use-case would greatly help single-sourcing in product
documentation.